In the recovery of gaseous substances from air, e.g. solvent vapors from the solvent-containing air driven off or released from dry-cleaning, degreasing and like machinery, it is known to circulate the air over an adsorbent through a receptacle containing same and, in a closed path, back to the machine in order to prevent release of air containing solvent-vapor residue, into the atmosphere.
In general, an adsorption installation for this purpose operates with two receptacles in which one is always in an operative mode for adsorbing solvent vapors from the air of the machine while the adsorbent is regenerated in the other by treatment of the adsorbent with steam.
In such regenerating or adsorbent systems, the steam, after traversing the adsorption agent (e.g. activated carbon) is passed into a condenser in which it is condensed together with the entrained solvent vapors.
The vapor-containing air within the receptacle to be regenerated, prior to the introduction of the steam, is usually vented into the atmosphere by being expressed from the steam through the condenser and the associated water separator which separates the condensed solvent from the condensed water. As a result, small quantities of air and entrained solvent vapors are released into the environment, i.e. solvent vapors are carried into the atmosphere.